The linchpin of the government’s criminal case against the ex-presidential candidate spent long hours driving to and from political events with the rising Democratic star. They attended college basketball games together to root for the Tar Heels and buddied around at Edwards’ beach house. Young was even tasked with buying Christmas presents for the Edwards children.

“We were just North Carolina boys and had a lot in common,” Young testified Monday. The men were so close that when Edwards got his mistress pregnant in 2007, the married Young publically claimed paternity of his boss’ unborn child.

The former aide was the first witness called by federal prosecutors Monday following opening statements in Edwards’ criminal trial, which is being held in Greensboro, N.C. Prosecutors allege that Edwards masterminded a conspiracy to use nearly $1 million in secret payments from two wealthy donors to help hide his pregnant mistress as he sought the White House in 2008.

Edwards, 58, has pleaded not guilty to six criminal counts related to alleged violations of federal campaign finance laws stemming from accepting money in excess of the $2,300 legal limit for individual contributions. Federal law defines campaign contributions as money given to influence the outcome of a U.S. election.

“It wasn’t just a marriage on the line,” prosecutor David Harbach said in his opening statement. “If the affair went public it would destroy his chance of becoming president, and he knew it. ...He made a choice to break the law.”

U.S. District Court Judge Catherine C. Eagles seated 12 jurors and four alternates Monday morning. The panel is made up of nine men and seven women drawn from central North Carolina. Edwards represented the state for one term in the U.S. Senate.

Edwards stared intently at Young as his former confidant testified. In nearly two hours of talking about Edwards, Young never looked in his direction.

For Edwards and his defense team, destroying Young’s credibility is key to their strategy of keeping the former presidential contender out of prison.

They allege that much of the money at issue in the case was siphoned off by Young and his wife to pay for a $1.5 million house finished in 2008.

“Follow the money,” defense lawyer Allison Van Laningham urged jurors in her opening statement. “John Edwards did not get any of this money. Not one cent.”

Edwards’ lawyers contend the payments were gifts from friends intent on keeping the candidate’s wife from finding out about the affair. Elizabeth Edwards died in December 2010 after battling cancer.

They also said Young pocketed most of the money and used it to help bankroll a $1.5 million home for his family.

Young thought Edwards was his "ticket to the top," the defense said. When things soured, he recruited others to testify against Edwards in the criminal prosecution, according to the defense.

Defense attorneys said Young called three witnesses in the past two weeks to find out what they would say at the trial, behavior that is frowned upon but not illegal.

Prosecutor David Harbach acknowledged that Young and his wife mixed their money with the payments meant for Hunter and spent some of it on a new home.

On Monday, Young told jurors how he met Edwards during the U.S. Senate campaign and became his right-hand man for the two presidential bids.

Young has admitted that parts of his 2010 tell-all book about Edwards, "The Politician," are untruthful, Harbach said.

"You will not like him," Harbach told jurors. "But remember this: Mr. Young is an exhibit as much as he is a witness."